US 7,511,450 B2
Frequency converter, motor, motor drive system and maintenance method for motor drive system
Tadahiro Shimozono, Yachiyo (Japan); Takeshi Obata, Narashino (Japan); Koichiro Saito, Funabashi (Japan); Osamu Matsumoto, Yachimata (Japan); and Kouji Obata, Hitachi (Japan)
Assigned to Hitachi Industrial Equipment System Co., Ltd., Tokyo (Japan)
Filed on Oct. 31, 2007, as Appl. No. 11/931,704.
Application 11/931704 is a continuation of application No. 11/783602, filed on Apr. 10, 2007, granted, now 7,408,323.
Application 11/783602 is a continuation of application No. 11/521486, filed on Sep. 15, 2006, granted, now 7,202,628.
Prior Publication US 2008/0061730 A1, Mar. 13, 2008
Int. Cl. H02P 23/00 (2006.01)
U.S. Cl. 318—807  [318/812; 318/800; 318/801] 1 Claim
OG exemplary drawing
 
1. A method of maintenance for a motor driving system having a frequency converter and a motor, wherein an output power from said frequency converter is applied to motor windings of said motor to drive said motor, said method comprising the steps of:
obtaining first characteristics and second characteristics, wherein said first characteristics indicate a relation between a rise time of a voltage to be applied to the motor windings and a value of a voltage at which a partial discharge will not occur between motor windings, and said second characteristics indicate a relation between inductances of reactors provided between the frequency converter and motor and a change in said rise time of the voltage;
obtaining, based on the first characteristics, a surge voltage suppressing rise time of a voltage output from the frequency converter is obtained at which the partial discharge is suppressed from being generated between motor windings;
obtaining, based on the surge voltage suppressing rise time and the second characteristics, an inductance satisfying the surge voltage suppressing rise time; and
arranging a reactor having the obtained inductance between the frequency converter and the motor.